On a dark night you can practically watch stars being born. The fuzzy area in the sword in the constellation Orion is the Orion nebula. A close up shows the nebula with around 3,000 stars. New stars are being born there.

Star Lives

Stars have a life cycle, just like people. Stars are born, grow, change over time, and eventually grow old and die. Most stars change in size, color, and class at least once in their lifetime. What astronomers know about the life cycles of stars comes from data gathered from visual, radio, and X-ray telescopes.

Nebulae

Stars are born in a cloud of gas and dust called a
nebula
(
Figure
below
). Our sun and solar system formed out of a nebula.

Stars are forming in the Rosette Nebula.

The Pillars of Creation (
Figure
below
) are within the Eagle Nebula. The pillars are thought to be a large region where stars are forming. The dark areas may be stars that are about to begin.

In the Pillars of Creation, gas and dust come together as a stellar nursery.

Star Formation

For a star to form, gravity pulls gas and dust into the center of the nebula. As the material becomes denser, the pressure and the temperature increase. When the temperature of the center becomes hot enough, nuclear fusion begins. The ball of gas has become a star!